Khamenei's remarks come after the US has indicated that Iran had carried out the September 14 attacks on two Saudi Arabian oil fields which led to a cut global oil supplies by 5 per cent and an increase in prices.
Speaking to the media, Khamenei said entering talks with the US under the current circumstances would be tantamount to surrendering to Washington's undue pressure campaign, reports Press TV.
"Negotiating would mean Washington imposing its demands on Tehran. It would also be a manifestation of the victory of America's maximum pressure campaign," the leader noted.
"That is why Iranian officials, including the President, the Foreign Minister and others, have unanimously voiced their objection to any talks with the US - be it in a bilateral or a multilateral setting."
Khamenei said talks with Iran would be possible only if the US returns to a 2015 nuclear deal that it abandoned last year.
Under that multilateral accord, Washington had lifted its anti-Iran economic sanctions.
"If the US retracts its words, repents and returns to the nuclear accord that it has violated, it can then take part in sessions of other signatories to the deal and hold talks with Iran... Otherwise, no talks at any level will be held between Iranian and American authorities, neither in New York nor elsewhere," Press TV quoted the leader as saying.
He also noted that the US policy of maximum pressure consists of "a range of sanctions, threats and rants", which are meant to bring Iran to the negotiating table.
The attacks on September 14 was carried out by 10 unmanned aircraft. It hit the Hijra Khurais - one of Saudi Arabia's largest oil fields, producing about 1.5 million barrels a day - and Abqaiq, the world's biggest crude stabilization facility, which processes seven million barrels of Saudi oil a day, or about 8 per cent of the world's total output.
Although the Yemeni Houthi rebels have claimed responsibility for the attack, US Secretary of State Mike Pompeo has denied it, saying: "There is no evidence the attacks came from Yemen", while blaming Iran instead.
( With inputs from IANS )